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A Silent Epidemic with Serious Consequences—What You Need to Know about B12 Deficiency


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Reviewed by Chris Masterjohn, PhD

This tired man rubbing his eyes may be experiencing B12 deficiency.
Fatigue is a common symptom of B12 deficiency.

What do all of these chronic diseases have in common?

  • Alzheimer’s, dementia, cognitive decline, and memory loss (collectively referred to as “aging”)
  • Multiple sclerosis (MS) and other neurological disorders
  • Mental illnesses like depression, anxiety, bipolar disorder, and psychosis
  • Cardiovascular disease
  • Learning or developmental disorders in kids
  • Autism spectrum disorder
  • Autoimmune disease and immune dysregulation
  • Cancer
  • Male and female infertility

Answer: Their signs and symptoms can all be mimicked by a vitamin B12 deficiency.

An Invisible Epidemic

B12 deficiency isn’t a bizarre, mysterious disease. It’s written about in every medical textbook, and its causes and effects are well-established in the scientific literature.

However, the condition is far more common than most healthcare practitioners and the general public realize. Data from a Tufts University study suggests that 40 percent of people between the ages of 26 and 83 have plasma B12 levels in the low normal range—a range at which many experience neurological symptoms. Nine percent had an outright nutrient deficiency, and 16 percent exhibited “near deficiency.” Most surprising to the researchers was the fact that low B12 levels were as common in younger people as they were in the elderly. (1)

That said, this type of deficiency has been estimated to affect about 40 percent of people over 60 years of age. It’s entirely possible that at least some of the symptoms we attribute to “normal” aging—such as memory loss, cognitive decline, and decreased mobility—are at least in part caused by a deficiency.

Why Is It Underdiagnosed?

B12 deficiency is significantly underdiagnosed for two reasons. First, it’s not routinely tested by most physicians. Second, the low end of the laboratory reference range is too low.

This is why most studies underestimate true levels of deficiency. Many deficient people have so-called “normal” levels of B12.

Yet, it is well-established in the scientific literature that people with B12 levels between 200 pg/mL and 350 pg/mL—levels considered “normal” in the U.S.—have clear vitamin deficiency symptoms. (2) Experts who specialize in the diagnosis and treatment of a deficiency, like Sally Pacholok, R.N., and Jeffrey Stuart, D.O., suggest treating all patients that are symptomatic and have B12 levels less than 450 pg/mL. (3) They also recommend treating patients who show normal B12 levels but also have elevated urinary methylmalonic acid (MMA), homocysteine, or holotranscobalamin, which are other markers of a deficiency in vitamin B12.

B12 deficiency can mimic the signs of Alzheimer’s, dementia, multiple sclerosis, and several mental illnesses. Find out what this vitamin does and learn how to treat a deficiency. #B12 #B12deficiency #cognitivedecline

In Japan and Europe, the lower limit for B12 is between 500 and 550 pg/mL. Those levels are associated with psychological and behavioral symptoms, such as:

  • Cognitive decline
  • Dementia
  • Memory loss (4)

Some experts have speculated that the acceptance of higher levels as normal in Japan and the willingness to treat levels considered “normal” in the U.S. explain the low rates of Alzheimer’s and dementia in that country.

What Is Vitamin B12 and Why Do You Need It?

Vitamin B12 works together with folate in the synthesis of DNA and red blood cells. It’s also involved in the production of the myelin sheath around the nerves and the conduction of nerve impulses. You can think of the brain and the nervous system as a big tangle of wires. Myelin is the insulation that protects those wires and helps them to conduct messages.

Severe B12 deficiency in conditions like pernicious anemia (an autoimmune condition where the body destroys intrinsic factor, a protein necessary for the absorption of the vitamin) used to be fatal until scientists figured out death could be prevented by feeding patients raw liver, which contains high amounts of B12. But anemia is the final stage of a deficiency. Long before anemia sets in, deficient patients will experience several other problems, including fatigue, lethargy, weakness, memory loss, and neurological and psychiatric problems.

The Stages of a Deficiency

B12 deficiency occurs in four stages, beginning with declining blood levels of the vitamin (stage I), progressing to low cellular concentrations of the vitamin (stage II), an increased blood level of homocysteine and a decreased rate of DNA synthesis (stage III), and finally, macrocytic anemia (stage IV). (5)

Common B12 Deficiency Symptoms

The signs can look like the symptoms of several other serious disorders, and the neurological effects of low B12 can be especially troubling.

Here are some of the most common vitamin B12 deficiency symptoms:

  • Tingling or numbness in the hands and feet
  • Brain fog, confusion, and memory problems
  • Depression
  • Premature aging
  • Cognitive decline
  • Anemia
  • Weakness
  • Fatigue
  • Reduced appetite and weight loss
  • Constipation
  • Trouble balancing (6)

Children can also show symptoms, including developmental issues and learning disabilities if their B12 levels are too low.

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Why Is It So Common?

The absorption of B12 is complex and involves several steps—any of which can go wrong. Any of the following can cause B12 malabsorption:

  • Intestinal dysbiosis
  • Leaky gut and gut inflammation
  • Atrophic gastritis or hypochlorhydria, or low stomach acid
  • Pernicious anemia
  • Medications, especially proton pump inhibitors (PPIs) and other acid-suppressing drugs
  • Alcohol
  • Exposure to nitrous oxide, during either surgery or recreational use

This explains why a deficiency can occur even in people eating large amounts of B12-containing animal products. In fact, many of my patients that are B12 deficient are following a Paleo diet where they eat meat two or three times daily.

Who Is at Risk for a Deficiency?

In general, the following groups are at greatest risk for a deficiency:

  • Vegetarians and vegans
  • People aged 60 or over
  • People who regularly use PPIs or acid-suppressing drugs
  • People on diabetes drugs like metformin
  • People with Crohn’s disease, ulcerative colitis, celiac, or IBS
  • Women with a history of infertility and miscarriage

Note to Vegetarians and Vegans: B12 Is Found Only in Animal Products

You cannot get B12 from plant-based sources. This vitamin is only found in animal products. That’s why vegetarians and vegans need to know the signs of deficiency—and the steps necessary to fix the problem.

B12 is the only vitamin that contains a trace element (cobalt), which is why it’s called cobalamin. Cobalamin is produced in the gut of animals. It’s the only vitamin we can’t obtain from plants or sunlight. Plants don’t need B12, so they don’t store it.

A common myth among vegetarians and vegans is that it’s possible to get B12 from plant sources like:

  • Fermented soy
  • Spirulina
  • Brewers yeast

However, plant foods said to contain B12 actually contain B12 analogs called cobamides that block the intake of and increase the need for true B12. (7) That explains why studies consistently demonstrate that up to 50 percent of long-term vegetarians and 80 percent of vegans are deficient in B12. (8, 9)

Seaweed is another commonly cited plant source of B12, but this idea is controversial. Research indicates that there may be important differences in dried versus raw purple nori; namely, raw nori may be a good source of B12, while dried nori may not be. One study indicated that the drying process used for seaweed creates B12 analogs, making it a poor source of the vitamin, while animal research suggests that dried nori can correct a B12 deficiency. (10, 11) Seaweed may provide B12, but it’s not clear if those benefits are negated when that seaweed is dried. I recommend caution for that reason.

The Impact of a Deficiency on Children

The effects of B12 deficiency on kids are especially alarming. Studies have shown that kids raised until age six on a vegan diet are still B12 deficient even years after they start eating at least some animal products. In one study, the researchers found an association between a child’s B12 status and their performance on testing measuring:

  • Spatial ability
  • Fluid intelligence
  • Short-term memory

Researchers found that formerly vegan children scored lower than their omnivorous counterparts in each area. (12)

The deficit in fluid intelligence is particularly troubling, the researchers said, because this area impacts a child’s ability to reason, work through complex problems, learn, and engage in abstract thinking. Defects in any of these areas could have long-term consequences for kids.

I recognize that there are many reasons why people choose to eat the way they do, and I respect people’s right to make their own choices. I also know that, like all parents, vegetarians and vegans want the best for their children. This is why it’s absolutely crucial for those that abstain from animal products to understand that there are no plant sources of B12 and that all vegans and most vegetarians should supplement with B12.

This is especially important for vegetarian or vegan children or pregnant women, whose need for B12 is even greater. If you’re not willing to take a dietary supplement, it may be time to think twice about your vegetarian or vegan diet.

How to Treat a Deficiency

One of the greatest tragedies of the B12 epidemic is that diagnosis and treatment are relatively easy and cheap—especially when compared to the treatment patients will need if they’re in a late stage of deficiency. A B12 test can be performed by any laboratory, and it should be covered by insurance. If you don’t have insurance, you can order it yourself from a lab like DirectLabs.com.

As always, adequate treatment depends on the underlying mechanism causing the problem. People with pernicious anemia or inflammatory gut disorders like Crohn’s disease are likely to have impaired absorption for their entire lives and will likely require B12 injections or high-dose oral cobalamin indefinitely. This may also be true for those with a severe deficiency that’s causing neurological symptoms.

Typically in the past, most B12 experts recommended injections over high-dose oral cobalamin for people with pernicious anemia and an advanced deficiency involving neurological symptoms. However, recent studies have suggested that high-dose oral or nasal administration may be as effective as injections for those with B12 malabsorption problems. (13, 14)

Try Supplementing

Cyanocobalamin is the most frequently used form of B12 supplementation in the U.S. But recent evidence suggests that hydroxocobalamin (frequently used in Europe) is superior to cyanocobalamin, and methylcobalamin may be superior to both—especially for neurological disease.

Japanese studies indicate that methylcobalamin is even more effective in treating neurological symptoms and that it may be better absorbed because it bypasses several potential problems in the B12 absorption cycle. (15, 16) On top of that, methylcobalamin provides the body with methyl groups that play a role in various biological processes important to overall health.

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Chris Kresser in kitchen

Change Your Diet

Nourishing your body through whole food is the best way to get the vitamins and nutrients you need. If you’re low on B12, try eating some vitamin-rich foods like:

Eating other kinds of seafood, like octopus, fish eggs, lobster, and crab, can also help you attain normal B12 levels. If you’re seafood-averse, you can also get this vitamin from:

  • Lamb
  • Beef
  • Eggs
  • Cheese

It’s important to note, though, that the amount of B12 in these foods is nowhere near as high as the levels in shellfish and organ meats.

What to Do if You’re Experiencing Vitamin B12 Deficiency Symptoms

If you suspect you have a deficiency, the first step is to get tested. You need an accurate baseline to work from.

If you are B12 deficient, the next step is to identify the mechanism causing the deficiency. You’ll probably need help from a medical practitioner for this part. Once the mechanism is identified, the appropriate form (injection, oral, sublingual, or nasal) of supplementation, the dose, and the length of treatment can be selected.

So, next time you or someone you know is “having a senior moment,” remember: It might not be “just aging.” It could be B12 deficiency.


Join the conversation

  1. Thank you for the great post and information Dr. Kresser!

    To those in doubt about the seriousness of B12 deficiency, I can tell you finding out the HARD WAY that you are deficient is horrible. In May 2007 when I was 30 I ended up in the hospital with a severe case a ataxia and nystagmus. I was in the hospital for 8 days, where I was initially diagnosed with MS. After almost every possible test available was performed on me (3 MRI’s, Cat Scan, Spinal Tap, blood tests every day, to name a few), they only thing that was wrong with me was a B12 level of 110, with sclerosis of the brain caused by the deficiency. Since then I’ve taken B12 shots every month, and have been much better. There was a period when I doctors were trying to wean me off of B12, but that caused me a severe metabolic imbalance, so I was back to B12 shots again.

    Right now, after new B12 tests, it was discovered that even though with the monthly shots I take, my B12 level is still low (475), which dropped to (261) after 7 weeks with no B12 injection. So, in addition to being back to B12 shots (of the Cyanocobalamin kind), I’m also supplementing myself with sublingual Methylcobalamin. Hopefully this will increase my B12 levels back to normal (I hope at least to 600), while my doctors try to figure out again where in the process I seem to not be assimilating B12 (I’m a meat-eatrian, with no reason WHATSOEVER to be deficient).

    Word of advice: The only reason why ((it seams)) I was not diagnosed with a B12 deficiency before, was because doctors had me labeled as having depression and anxiety, which was causing me to have low body weight -all bullshit!. They had me on medication which improved my mood, but physically I was still deteriorating. I had to end-up in the hospital for anyone to realize my B12 deficiency.

    Anyhow, wish me luck!
    But seriously, if you’re vegetarian or vegan, or if you find yourself tired and achy all the time and unable to keep a decent weight, have your b12 level check -it is worth it!

    Dr. Kesser: Are there any other tests I should demand from my Doctors? The only one I know they did, was Intrinsic Factor, and supposedly that one came negative. Any help would be appreciated!

  2. I recently moved from Scotland down to England ….. I was diagnosed with PA over 20 years ago and have been having injections of B12 6 weekly for the past 10 years ( prior to that I started for a few years 12 weekly then went to 8 weekly ) When I registered at my new GP he refused to give me by injection ( which was due ) until I had a blood test. The test came back with B12 levels of 1152 …… and he is now refusing to give me my injection until results of a further fasting blood test are back.
    I am beginning to panic now …… not only ( because my injection is nearly a week overdue ) do I feel lethargic, headachy, woolly headed and generally unwell, but I am not sleeping at all because I am so worried this GP will refuse to give me B12 jabs at all. Within 36 hours of having my injections I always feel ‘ back to normal ‘ bright, alert and my headache disappears …… I feel my life ( and that of my family ) will be ruined if I don’t have my regular injections. What I can’t understand is why …. after 20 years of my B12 injections alleviating all the awful symptoms I get, this GP can think for one minute I don’t need them ?? I know my levels were high in the blood test but surely the remarkable change in how I feel after having my jabs speaks for itself ??

  3. O.k. so here’s my question… my B12 has been falling steadily for about a year despite taking 1000 units of B12 a day… first 186, then 170, fell to 156, was 130, and so my GI specialist tested me for pernicious anemia ( I should mention I’ve also been dx’d with Fibromyalgia last March). I’m still waiting for the results and it’s been over a week since the test (tested the B12 level too… I suspect it is lower given my level of fatigue, brain fog, and hand foot involvement). I’ve recently had a plethra of other issues, including sternum pain, rib pain, chest pain that radiates to my back in and around my left shoulder blade, and hip pain. All of this feels unlike my Fibo symtoms, and more like bone pain. So let me get back to my question… If this pernicious anemia test is negative… should I be worried? Could there be another serious underlying problem?
    Thanks for your time and assistance.

    • Hi Kristin,

      I am not a doctor but your description reminds me of an autoimmune condition I was diagnosed with. The rib, sternum and back pain get worse when laying down and are somewhat relieved by movement. Google reactive arthritis or ankylosing spondylitis.

      I’ve also had a lot of neuro symptoms similar to what have been described in this thread. My doctor has me on B 12 and at times I have been anemic in the past.

      Anyhow, good luck!

  4. I started with sensory problems and pain in my joints when I was about 21, shortly after the birth of my son. Long story short, after seeing several doctors and having some investigations they decided I had fibromyalgia. I wasn’t so convinced by the diagnosis as although I exhibited many of the symptoms I had many other symptoms that were not covered by the fibromyalgia umbrella however, feeling like the Dr’s were seeing me as some crazy hypochondriac I had to accept their decision and just get on with things, albeit with the assistance of crutches as I could no longer walk unaided.

    Fast forward 5 or so years during which time I had many symptoms such as intermittent burning feet, with intense pins and needles which I casually mentioned to my haematologist (I have an auto immune disease chronic idiopathic thrombocytopenia) who said it had nothing to do with my blood problem and did not investigate further. Then I noticed that my fingernails had developed ridges in them and decided to see if I perhaps needed a vitamin supplement as i have been vegetarian for 20 years. After a search online I was shocked to see the signs and symptoms of b12 deficiency, many of which I clearly had, I went completely grey by the time I was 25 and no one seemed to see this as an indication of anything being wrong.

    Next time I went to my haematologist I asked him to test my b12 levels at my next routine 3 monthly blood test, he agreed but said it would be unlikely to be low. However, they were at 192 and when I went to get these results I actually saw a different doctor due to mine being busy with new patients and I had to ask if the results had come back … kind of expecting them to be normal and she looked and said … hmm, yes they are low …. and your iron has been low …. forever. She put me in for more tests for the intrinsic factor, celiacs and thyroid test and for a repeat b12 test in 3 months with no supplements in the meantime. When I went to get the results, the intrinsic/thyroid and celiacs test results were not back but my b12 had dropped further to 183 and my iron levels had also dropped.

    My consultant has put me on monthly b12 injections and is seeing me again in three months. Had my first jab today so of course have not felt any benefit yet but I hope to perhaps in the future, although I would imagine that much of the nerve damage I am exhibiting is now irreversible.

    One other thing i would like to mention is that from time to time I have been treated with short term, very high doses of steroids and long term lower doses of steroids for my thrombocytopenia when my platelets have been very low, during these times I felt a great deal better in myself as a whole, I read something yesterday about steroids actually helping the absorption of b12 or something along those lines and wonder if this is why I always felt so well on steroids and so dreadful when not.

    Doctors really need to be on the ball with this, luckily even though I have to walk with elbow crutches and am in a lot of pain on a daily bases I have managed to stay in work and still contribute to society but this has only been due to my own determination and I am sure there must be a lot of people out there on welfare etc when a simple b12 shot could allow them to lead full and healthy lives. I have written to the BBC today about my case and am hoping that some media exposure could really get this discussion going especially with regards to the so called ‘normal levels’ decided by the NHS, which are clearly too low.

    Sorry for the long post and I understand if anyone says tldr … but I felt it important to give the whole picture

  5. Hi. Very Interesting information. I had a B deficiency test done a month ago. Dr. Sent it off to Mayo Clinic. A week later I had a notice of Urgent and a phone call. Dr. ordered me to take 50 mg of B6. I went and bought a liquid b complex that has 50mg of b6 in it. I take medication due to anxiety, and antidepressant zoloft. I have been on zoloft for 14 yrs. I have been taking the B complex for two weeks now and I am getting these “zaps” all over. This I was told was from a neurological problem …this happens every time I stop my zoloft for 2 days, however since I have been taking the B complex, and the zoloft…the zaps are here, I feel weird and am really confused feeling…what is going on? This is really scary to me because it appears the zoloft does something to the neurological system and this b complex is battling that. The reason I asked Dr. for B test, is I was having very bad symptoms for along time…including swelling of lymphatic system…throat, neck…different area’s of internal areas of body, very bad digestive problems, anxiety, pmdd, or a form of mild depression, I am certain there is some link to this with my medications and B …..and my son…he is high functioning autistic…could this be a problem as well. My Dr. had said that B deficiency (not just B12) is very rare. Why did he order B6? I really am praying for some ideas or tests to ask for or what kind of dr. I should see because my family Dr. seems to not know a whole lot about this. Your advice would be very appreciative. 🙂

  6. I have not been eating meat and have had neuro problems. I will resume meat. How much do I need? Is a couple of buffalo or hamburgers a week enough? I will ask my neuro to give me rx for b12 injection. I have had inner tremors and one episode of violent shivers along with nerve pain and swollen tongue, mouth and tongue sores. Also diagnosed with eosinophilic esophagitis. Any connection between that and B12 absorption problems?

  7. Hi I’ve been reading these posts with a lot of interest. I was diagnoised with b12 deficiency four years ago and given oral b12 my levels increased and tingling and vibratingfeelings got much better my levels were 158. My gp took me off b12 twice as my levels were high but my symptoms cane back. Object changed my gp and my levels were 258 the gp told me they were normal and refused to treat me. I told him that my levels were158 at one point so he gave me an injection this helped the symptoms but they did not go like they had previously so I asked for more frequently injections so I’m on one every two months. The go told me the symptoms were not due to by b12 level ad they were normal at 377 I still have symptoms the gp referred me for verve conductive tests which were 100 per cent normal and now I’m referred to a neurologist and I’m worried it’s ms but my symptoms were ok when I was on 50 mcg tablet per day. Are theses symptoms of ms?

  8. Thanks for the informative post; what brand and dose of B-12 do you recommend? Not sure if you want to endorse but couldn’t find any recommendations as I tried to slog thru the long thread. Thanks in advance!

  9. Hello I came across your website and I just wanted to ask you some questions regarding b12 deficiency. I have many symptoms of the deficiency like anxiety. Panic attacks, loss of balance, foggy mind. They tested my b12 level and it was at 372. Which to some is believed to be within the normal range which is confusing to me as to why I have the above symptoms. Anyhow I take 1000mcg of b12 time released a day but I just started 3 days ago. I was wondering if 372 is in fact low enough to have symptoms as well as cause alzheimers and irreversible damage? Also how much b12 should I take daily? And this might sound ironic but when I take the b12 I feel a little anxious and have a little trouble sleeping, could that be from the b12 pill? I eat plenty of meat, chicken and all kinds of food so I am not sure how I got this low. Also is it better to take sublinual vs oral capsules? I just want some solid good answers from an expert. I appreciate your help thank you so much,

  10. 51 years of age and working a 3 way police shift pattern full time. Underactive thyroide diagnosed 18 years ago, B12 deficiency diagnosed 5 years ago. I was anemic last year.

    I have been to the doctor for test 3 times now with complete exhaustion, aching legs, arms, neck and bad headaches. Tests show now my folic level is low. On 3 monthly b12 injection. I need my brain for work, but body and concentration is letting me down.

    The question are:- Does anyone have flue like symtoms after their b12 injections and is there anything else I can do to help my conditions.

    • Have you considered being tested for gluten intolerance? I was 59 when I finally realized that gluten was wreaking havoc in my body. Since going gluten free, my chronic fatugie has vanished. Also, B12 is hard to absorb from the small intestine if it has become damaged by gluten. My personal opinion is that gluten should be banned, period. Google gluten intolerance and the diseases it causes. You’ll be shocked.

  11. Hi Chris,

    I have some terrible symptoms and I am not sure if they are related to b12 difficiency or maybe some cortisol problem( i have pcos and insulin resistance)?

    The symptoms are: numbness and tingles troughout the body and face, severe heat and tingles in the faceand head(sensation like fever) , bloodshot eyes, sudden weakness and deconcentration and memory loss. These symptoms are the worst just after a meal! ( I eat low carb Paleo).

    What do you think it could be?Thanks!

  12. Hi Chris,
    I am just wondering if there is a link between low b12 levels and osteoporosis. I’m in my late 30’s and was diagnosed with osteopororis a couple of years ago (at the time it was thought it was brought on by use of steroids as I am an asthmatic, but the medics never got to the bottom of it). I am on Calcium & Vit D supplements but nothing else due to being of child bearing age. I had low B12 levels a number of years ago and received a course of injections at that time, but it was something that was never really checked after that until last year when I started to have scary neurological issues with muscle twitching, muscle cramps particularly in my lets, feet etc. The muscle twitching was scary experience happening over my whole body for weeks on end. My Gp ran some more tests and came back with low B12 and high platlets. My blood pressure has been on the high side on occasions over the last year. While a course of weekly B12 shots helped with the neurological issues, it was decided I would have 3 monthly shots. What was recently noticed by the GP is that while my B12 increases after shots, it falls dramatically after 3 months and thus GP has agreed to give me monthly shots just recently. I also suffer alot with colds and flu’s which I am beginning to think is linked to perhaps a low immune system as a result of the low b12 – could this be right? I’m an asthmatic so the cold/ flu experience is always that bit worse when I get it.
    I am just wondering what your advice is on the links. Pernicious anaemia was something my GP has never mentioned – should I look into this also? How is this diagnosed? I don’t think my FBC/ CBC has ever come back stating I’m low in iron so maybe this is not an issue. Maybe now that the GP has agreed to monthly shots, that is all I need to do. Any advice at all would be much appreciated. I am also interested if you have any advice on the low b12 / osteoporosis link. I am delighted I came across your site – I don’t think often this issue is taken seriously enough. Many thanks, SuzieD

  13. Thanks Chris for your quick response!
    Yes I did get the anti-parietal cell antibody test done in March ’10. It came back positive whereas my intrinsic factor came back negative. My understanding was if those were the readings I did not have pernicious anemia???
    On a side note, at that time, my Ferritin level was 9 ug/L. Also my Folate was >45.0 nmol/L. As of July ’11 my Ferritin is 12 and Folate is >40.0

  14. In Dec. ’09 I was diagnosed with a B12 deficiency. My level was 85. I started with 1000 mcg injections of cyanocobalamin daily for 5 days. Then progressed to weekly until May of ’10 and since then have been getting injections every 3 weeks. My last level reading in July ’11 was 279.
    In Nov. ’10 I was diagnosed with Subacute Combined Degeneration of the Spinal Cord. I use a cane to walk due to my balance issues. I have next to nothing for vibration sense though my reflexes are increased. In the dark or when I close my eyes my balance is severely compromised. Tingling and numbness are present in my hands and especially my feet. My short term memory and concentration have been affected.
    It is confusing to me that none of the physicians I have seen are very concerned as to why, in the first place, I developed the deficiency. I am not a vegetarian, I do not drink, have not had stomach surgery of any kind. I did get tested for parietal cell antibodies ….. positive …. and for intrinsic factor antibodies …… negative. Not really sure what that means if it means anything.
    Also confusing is to why some of the doctors I have seen are saying that my symptoms would appear to possibly be non-organic?? One says one thing, one says another. According to them my levels are “normal” and I should be better by now. If I think back, I have been dealing with odd symptoms and had 2 emergency room visits before my diagnosis in Dec. ’09. Quite possibly if someone had checked my levels then it would have shown and I wouldn’t be dealing with this 22+ months later??
    If anyone has any ideas or more questions I should be asking, thank you in advance!

    • Mona: were you tested for pernicious anemia? That’s the autoimmune disease that causes severe B12 deficiency. Anytime I see levels as low as yours I immediately suspect that. Ask your doctor to test your anti-parietal cell antibodies. 90% of people with pernicious anemia will test positive for them.

      • Hi Chris
        I have really enjoyed reading your postings! Just recently I have been diagnoised with B12 deficiency. I am a 65 year old female. Oct./Nov., 2010 I was hospitalized for 22 days for breathing difficulty, severe swelling of body, especially feet and legs. Upon hospitalization my RBC was at 4. I was immediately given an !PO injection to stimulate my red cell count. However, my count did drop to 2. It would then rise a point or two, then drop a point. This happened for over a week. I do understand that I had double Phneumonia which would account, along with the extremely low RBC, my difficulty with breathing. Also, 2 liters of fluid was drawn from behind my rt. lung. Gradually my RBC did raise, and I was released from hospital when it was at 8. Dr’s. never did find a cause for my low RBC, nor for the unusual color of the fluid drawn from behind lung. After 22 days of test after test, no cause was found for my LOW RBC, nor for why it took so long for the count to rise. However since then, I am doing much better. At my last Dr. appt. Dr. said B12 low, gave me an injection and prescribed me Cyanocobalamin 1000MCG/ML. I forgot to mention that I also have acid reflux and IBS which keeps me house-bound often. Since my hospital stay I have gained a little over 25 lbs. and do retain a lot of fluid. My weight gain is NOT due to over-eating as most Dr’s. would want me to believe. Is there anything you might recommend me? ANYTHING would be appreciated!


        • Linda,
          My IBS went away when I treated my B12 and Vitamin D deficiency, which includes stopping my PPI (Acid reflux medication). Get the book Your Inside Tract by Gerard Mullin and Could it Be B12. I lost 31 pounds so far ONLY by stopping acid reflux medication and starting B12 and D3. Find a naturopath or an integrative medicine doc to help you get your acid reflux under control using natural means. I take HCL tablets before meals. I rarely have bad reflux anymore. I am 41 and was on PPIs daily for almost 20 years. I had IBS 15 out of 30 days in Jan, Feb and March. As soon as I started treating my B12 and D deficiencies it was GONE.

          • I’m not sure where to create a post so I am just responding here. I am a vegetarian and I can say emphatically that you CAN get B12 from nutritional yeast – NOT brewer’s yeast and NOT yeast that we all cook with. I put a tablespoon in my oatmeal every day. My folate, serum is 21.2 and my Vitamin B12 serum is 1044. I’m not hawking any particular product; I order mine from amazon, but your local health supply store may carry it. It has somewhat of a nutty flavor. So before doing anything else, I’d at least give the nutritional yeast a try. My GP asked ME how I have such good numbers.

            • Nutritional yeast only contains B12 because it has been added to it = fortified. It is NOT naturally occurring, lest someone be deceived.

              Eating this yeast may well be a good choice, but make sure it is indeed fortified as not all are and therefore not all have B12.

              “It is a source of protein and vitamins, especially the B-complex vitamins, and is a complete protein. It is also naturally low in fat and sodium and is free of sugar, dairy, and gluten. Sometimes nutritional yeast is fortified with vitamin B12.” [http://en.wikipedia.org/wiki/Nutritional_yeast]

              “Nutritional yeast is grown on enriched purified cane and beet molasses under carefully controlled conditions. T6635, with the addition of vitamin B12, is an ideal vegetarian support formula and has an appealing cheese flavor. It can be sprinkled over popcorn or salads, added to juice, cereal, smoothies, gravies, soups or casseroles, or used to make sandwich spreads.” [http://www.bobsredmill.com/nutritional-yeast.html]

              “The vitamin B12 component in B12 supplements and fortified foods is made by bacteria and sourced from bacteria cultures; it is not taken from animal products. However, some companies might put gelatin in their B12 supplements, though this appears to be less and less common. It is easy to find vegan B12 supplements on the Internet or in grocery stores in developed countries.”
              “There are many vegan foods fortified with B12. They include non-dairy milks, meat substitutes, breakfast cereals, and one type of nutritional yeast.”
              “Brewer’s and nutritional yeasts do not contain B12 unless they are fortified with it. There is at least one vegan, B12-fortified yeast currently on the market: Red Star Vegetarian Support Formula. (Twinlab’s SuperRich Yeast Plus contains whey).”[http://www.veganhealth.org/b12/vegansources]

              “itamin B12 is only produced in bacteria. No plant or animal is known to produce vitamin B12. This is why we require dietary sources of this vitamin to meet our nutritional needs. Many animals, however, are able to concentrate and save vitamin B12 produced in bacteria. As such, animal foods end up being important sources of this vitamin. Plants do not concentrate or utilize vitamin B12 in the same way as animals, so plant foods do not provide this vitamin.

              Seafoods, in particular, concentrate vitamin B12 well. All eight of our listed excellent sources of vitamin B12 are seafoods. A single serving per day of many types of seafood will meet or exceed your daily intake requirement. Older sources may claim that some plant foods—tempeh or spirulina, for instance—can be good sources of vitamin B12. This is because the laboratory assessments we use to find the small amounts of this vitamin in foods can pick up the presence of related (but different) compounds. The only usable vitamin B12 you’ll find in plant foods is residual from manure or bacterial contamination.

              Nutritionists currently recommend strict vegetarians or vegans use fortified foods or supplements to ensure proper vitamin B12 intake. For our readers that follow this dietary pattern, we agree with this public health recommendation.

              Nutritional yeast grown on a molasses medium is an example of a food-based quasi-supplement approach that would provide a vegan source of vitamin B12. One widely available brand has more than twice the Recommended Dietary Allowance (RDA) for B12 in one and one-half tablespoons of yeast. Note that not all nutritional yeasts are rich in vitamin B12, and that you’ll need to check labels for details.” [http://www.whfoods.com/genpage.php?tname=nutrient&dbid=107]

  15. Hum, I was just going to add the same thing — I had read an article recently stating that the “methylmalonic acid concentrations (either serum or urine) are a much more reliable metabolic measure of vitamin B12 metabolism”. Article can be found here:


    It is also mentioned in this article that produce grown in cow dung may contain more B12 than commercially grown produce. The author does not go into detail about this, but I wonder if one can conclude from this comment that healthy cows eating grass (and not fed antibiotics) would produce in their gut healthy bacteria that produce B12 and when their dung is used for fertilizer on human crops (assume no pesticides), the beneficial bacteria and their B12 producing capability is passed on to humans.

    To me, the ramifications of this is staggering — the pesticides and artificial fertilizers used in food production not only destroy the life in the soil, they deprive our bodies of the beneficial bacteria we need to produce B12. Add to that formula our medical system that uses antibiotics, vaccines and pharmaceutical drugs that all destroy beneficial flora in the gut and you have a recipe for disaster! I firmly believe that we have unprecedented levels of mental illness in this country due to lack of B vitamins, particularly B12, due to the destruction of beneficial B producing bacteria by the above methods.

    Dr. Campbell-McBride has written “Gut and Psychology Syndrome” and describes how the destruction of beneficial bacteria in the gut leads to damage of the gut which can produce a host of symptoms and illness — from dsylexia, ADD and autism to bipolar and schizophrenia. I would add to that list Alzheimer’s. She uses diet including bone broth, fermented foods and probiotics to heal the gut. There is a yahoo group for families following Dr. Campbell-McBride’s protocol for support and sharing of ideas. There are many inspiring stories of autistic children speaking for the first time after following Dr. Campbell-McBride’s protocol.

    I have suffered from B12 deficiency for a long time. I believe my B12 deficiency stems from 8 mercury fillings at age 12 as my health declined after that point. Now I also have a hernia and stomach ulcer which further contributes to my digestive issues and inability to absorb B12. I used sublingual B12 for years with okay results. I did not want to do injections myself and I do not have health insurance.

    However, the best results I have found for getting B12 have been to take a probiotic recommended by Dr. Campbell-McBride. The probiotic is Bio-Kult, it’s made in the UK and it contains a soil bacteria which Dr. Campbell finds the most helpful in treating autism. When I compare the results with this probiotic and taking sublingual B12, I feel 100 times better on the probiotic. My sleep, mental state and ability to think have improved dramatically. I seriously wonder if those with a high IQ might just have more B producing bacteria in their gut.

    One last comment — a friend recently returned from France and she told me she was denied a B12 shot. The physician told her that they have found a connection between B12 injections and cancer so they are limiting B12 injections to 4/year. This cannot be good for those of us with severe B12 deficiencies.

    Thank you for the article and I appreciate all the thoughtful comments.

    • Serum MMA is notoriously inaccurate and is not a good measure of B12 deficiency. Urinary MMA is accurate, and can be used along with homocysteine to determine B12 deficiency in cases where patients may have a falsely elevated serum B12 level (i.e. alcoholism, liver disease, intestinal bacterial overgrowth, lymphoma, etc.)

  16. Chris –

    Great post.

    I’d like to add the fact that B12 deficiency, while a huge issue, is not the largest problem.

    There is a genetic defect in the MTHFR gene which causes serious implications – similar to the B12 deficiency but escalate the effects more broadly and more seriously.

    Given that more than 50% to 70% of the population has one of more mutations in their MTHFR gene, it is an important one to evaluate in people.

    If someone has the MTHFR mutation, and they supplement with inferior forms of B12 such as cyanocobalamin, they are not able to transform it into the active form of methylcobalamin.

    The doctor will test their ‘serum cobalamin’ levels and say they are ‘fine.’ The issue is the serum cobalamin is a measure for the inactive B12 form – not the active form. That said, it is crucial to test for methylmalonic acid (MMA) to truly identify a vitamin B12 deficiency.

    What does this have to do with MTHFR mutations?

    People with MTHFR mutations cannot methylate B12!

    I am making this one of my specialties as people are not getting the information they need on it nor are they getting doctors knowledgeable in it.

    To understand the conditions which MTHFR may play a role in, I’ve written an article here:

    I hope you and I can do a podcast on this very important subject soon.

    In health,
    Dr Ben

  17. Hi Chris,

    I’m June all the way from St Andrews in Scotland…across the pond so to speak. Very interesting info’ you have there and thanks so much for sharing. I could spend all day reading the stuff, ( but I got lost after the 22nd posting and require laymen terms PLEASE!) I want to know what type of B12 do you recommend I buy, what brand and where can I purchase it whilst on a tight budget. As you know we ain’t doing so good, at the moment, on the financial front in the UK.
    Very hard to get a GP who will test you for vitamin and mineral deficiencies, still a bit of the old school stiff upper lip attitude over here regards new ways of thinking, but that is changing.

    Thanks so much and hope to hear from you soon
    Kind regards

    • It’s the same here in NZ, June. Can’t get vitamin and/or mineral tests at all. As far as B12 supplementation goes, as far as I understand it, sublingual B12 is the best. Solgar puts one out, 1000mcg tablet. I am using methylcobalamin (B12) drops. They’re only 50mcg but I take as much as I want of them each day.

  18. I found that I have a b12 deficiency and I began supplementing with methylcobalamin. Even 1mg sublingual seems to upset my stomach and I feel pretty spacey and weird. I have trouble sleeping as well and I always take the b12 in the morning. Any advice?

  19. Please excuse all of my typos. I was just so excited to read the other testimonials, that I was so much in a rush to give mine. Woopsie!! 🙂

  20. Hey all!!
    I stopped eating both read meat and pork about 11 years ago now. WOW, just did the math and didn’t realize it was so long ago. I am currently 23 years old. About 4 years after I had stopped eating red meat, my mother began to notice that I had been forming dark circles under my eyes. I had assumed it was due to a lack of rest because I was always on the go. I slowed down on my activities, and they darkness went no where. When I began Undergrad, it was very often that I would feel tired. Not only was I tired, but when it would come down to studying, I would be in the library for hours trying to retain information. In highschool, I was an honor-roll student, and I loved to learn, but this made me feel dumb. On my internship I would feel veryyyy tired, and would occasionally doze off. It wouldn’t matter how much coffee, or how many energy drinks I would consume, nothing really worked. I became extremely embarrassed, and this is when I began to feel as though something may be wrong with me. My mother encouraged me to take multivitamins and doing so made me feel a little better, but I began to neglect those. Since I graduated from Undergrad in 2009 I’ve had a hard time holding a job because of my dyer need to rest (falling asleep on the job). I started to think I has some sort of sleeping disorder or something. I had to get a physical for a job, and 3 weeks after the physical, I received a letter from the physician stating that were defenciencies found in my blood test. I ignored the letter because I was scared to find out what the issue was. My present job asked me not to go back into work until I was tested for narcolepsy due to falling asleep on duty (again). It was at this point that I that it was crucial for me to find out the results of my blood test in hopes that it will give me an answer to my weak, fatigued, cloud-minded body. Come to find out….my B12 is extremely low (says my physician). The first thing she asked me was if I ate red meat. She told me to go to the pharmacy and get the B12 vitamins. The thing that tripped me out is that something so simple had such a bigggg effect on my life!! I’ve been taking the B12 and seriously…this is no placebo or anything. I know my body and how it felt before and omgggg!!! What a difference!! No naps needed throughout the day, I feel sooo much better!!!! WOW!! Ok sorry for the novel but I just wanted to share that with you all!!! *be blessed*